PHP新的连接MySQL方法mysqli (2)

rollback - rolls back the current transaction
 select_db - selects the default database
 set_charset - sets the default client character set
 ssl_set - sets ssl parameters
 stat - gets the current system status
 stmt_init- initializes a statement for use with mysqli_stmt_prepare
 store_result - transfers a resultset from last query
 thread_safe - returns whether thread safety is given or not
 use_result - transfers an unbuffered resultset from last query
属性
 affected_rows - gets the number of affected rows in a previous MySQL operation
 client_info - returns the MySQL client version as a string
 client_version - returns the MySQL client version as an integer
 errno - returns the error code for the most recent function call
 error - returns the error string for the most recent function call
 field_count - returns the number of columns for the most recent query
 host_info - returns a string representing the type of connection used
 info - retrieves information about the most recently executed query
 insert_id - returns the auto generated id used in the last query
 protocol_version - returns the version of the MySQL protocol used
 server_info - returns a string that represents the server version number
 server_version - returns the version number of the server as an integer
 sqlstate - returns a string containing the SQLSTATE error code for the last error
 thread_id - returns the thread ID for the current connection
 warning_count - returns the number of warnings generated during execution of the previous SQL statement
 
 4. 基本语法      <?php
   
    /* Connect to a MySQL server  连接数据库服务器 */
     $link = mysqli_connect(
                'localhost',  /* The host to connect to 连接MySQL地址 */
                'user',      /* The user to connect as 连接MySQL用户名 */
                'password',  /* The password to use 连接MySQL密码 */
                'world');    /* The default database to query 连接数据库名称*/
   
    if (! $link) {
       printf("Can't connect to MySQL Server. Errorcode: %s ", mysqli_connect_error());
       exit;
    }
   
    /* Send a query to the server 向服务器发送查询请求*/
    if ( $result = mysqli_query( $link, 'SELECT Name, Population FROM City ORDER BY Population DESC LIMIT 5')) {
   
        print("Very large cities are: ");
   
        /* Fetch the results of the query 返回查询的结果 */
        while(  $row = mysqli_fetch_assoc( $result) ){
            printf("%s (%s) ",  $row['Name'],  $row['Population']);
        }
   
        /* Destroy the result set and free the memory used for it 结束查询释放内存 */
        mysqli_free_result( $result);
    }
   
    /* Close the connection 关闭连接*/
    mysqli_close( $link);
    ?>